c# - Get file type in .NET

Question

How can i get type of file using c#. for example if a file name id "abc.png" and type of file will "PNG Image" same as third column "Type" in window explorer.

Answer 1

You'll need to P/Invoke to SHGetFileInfo to get file type information. Here is a complete sample:

using System;
using System.Runtime.InteropServices;

static class NativeMethods
{
    [StructLayout(LayoutKind.Sequential)]
    public struct SHFILEINFO
    {
        public IntPtr hIcon;
        public int iIcon;
        public uint dwAttributes;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
        public string szDisplayName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
        public string szTypeName;
    };

    public static class FILE_ATTRIBUTE
    {
        public const uint FILE_ATTRIBUTE_NORMAL = 0x80;
    }

    public static class SHGFI
    {
        public const uint SHGFI_TYPENAME = 0x000000400;
        public const uint SHGFI_USEFILEATTRIBUTES = 0x000000010;
    }

    [DllImport("shell32.dll")]
    public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbSizeFileInfo, uint uFlags);
}

class Program
{
    public static void Main(string[] args)
    {
        NativeMethods.SHFILEINFO info = new NativeMethods.SHFILEINFO();

        string fileName = @"C:SomePathSomeFile.png";
        uint dwFileAttributes = NativeMethods.FILE_ATTRIBUTE.FILE_ATTRIBUTE_NORMAL;
        uint uFlags = (uint)(NativeMethods.SHGFI.SHGFI_TYPENAME | NativeMethods.SHGFI.SHGFI_USEFILEATTRIBUTES);

        NativeMethods.SHGetFileInfo(fileName, dwFileAttributes, ref info, (uint)Marshal.SizeOf(info), uFlags);

        Console.WriteLine(info.szTypeName);
    }
}